To our knowledge, only a few of the previous studies considered the effect of the AGN contribution on the morphological classification of their host galaxies. [1]} studied the effect of AGN on the rest-frame colours using a sample of X-ray detected obscured and unobscured AGN in the Extended Chandra Deep Field-South (ECDF-S) at 0.8 \(\le \)  z \(\le \)  1.2. They found an insignificant effect of the AGN on the galaxy colour in the case of moderate luminosity, obscured AGN, with a more significant effect for very blue, very luminous AGN (sources out of the blue cloud being classified as quasars, see their Fig. 1). A similar study considering the effect of AGN on the host colours has been carried out by [2]} for AGN of moderate X-ray luminosity up to the redshift of z \(\sim \)  2.5; again significant difference is found in the distribution of U - V rest-frame colour between active and non-active galaxies. These results go in line with several others showing that in moderate luminosity AGN, the AGN contribution to the total optical light is not significant [3]}, [4]}, [5]}.
